It has long been recognized as desirable to incorporate a lumbar support in the back of a seat. Particularly in the field of seats for automotive use, many different forms of lumbar support have been proposed. Examples are disclosed in U.S. Pat. Nos. 4,182,533 (Arndt, et al.), 4,313,637 (Barley) and 5,217,278 (Harrison, et al.). In general, these patents disclose lumbar supports that can be set at various positions in which the support protrudes from the seat back to provide different degrees of support.
In general, seats for office chairs have included only fixed (non-adjustable) lumbar supports.
Accordingly, an object of the present invention is to provide a lumbar support which is suitable primarily (not exclusively) for use in an office chair, and which is adjustable to provide different degrees of support.